Spark plug



Oct. 23, 1923;" v

v M. J. DOWNEY ET AL SPARK PLUG Filed Oct. 14 192D gin wanton! Tvbd-Dowaqey. M-M-Dowuey- J-D0wNe v i attoznup ll atcnted Got. 23, 1923.

UNETED fiTATES PATENT @FFHCE.

MILLARD J. DOWN'EY, MAURICE M. DOWNEY, AND JAMES DOWNEY, OF CHICAGO, ILLINOIS.

SPARK PLUG.

To all whom it may concern:

Be it known that we, MILLARD J. DOWNEY, MAURICE Ml DOWNEY, and JAMES DOWNEY, citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and ment will, incident to the movement thereof,

operate to maintain the main electrode of the plug clean.

And the invention has as a still further object to provide a plug wherein the sparking element will also be free for rotation so that in the operation of the plug, rotative radial shifting of said element will serve to constantly change the position of the sparking points thereof with respect to the confronting area of the shell.

Other andincidental objects will appear hereinafter.

In the accompanying drawings:

Figure 1 is a fragmentary vertical sectional view of my improved plug.

Figure 2 is a bottom plan view particularly showing the shape of the sparking element of the plug, and

Figure 3 is a detail elevation showing a slight modification of the invention.

In carrying the invention into efi'ect, We employ a shelllO threaded at its lower end portion for engagement in the spark plug orifice of an engine cylinder. Removably seated in the shell is a porcelain 11 secured by a nut 12 threaded into the upper end'of the shell. A gasket 13 is arranged between the porcelain and the shell while a similar gasket 14 is arranged between the porcelain and the nut. Extending axially through the procelain is a main electrode 15 projecting below the lower end of the shell and threaded upon the upper end of said electrode is a lock nut 16 seating against a suitable washer resting upon the upper end of the porcelain. Confronting the nut seen, serve to maintain the lower end 16 is a thumb nut 17 adjustable upon the electrode for binding a circuit wire between the nuts.

Formed on the lower end portion of the electrode 15 in spaced relation to the lower end of the shoulder or collar 18 and freely mounted upon the electrode is a sparking element 19, the electrode being upset at its lower end for retaining said element thereon. As particularly shown in Figure 2 of the drawing, the sparking element is preferably star shaped being, in the embodiment of the invention shown, provided with six radial projections or arms 20 e ually spaced with respect to each other. hese projections are each notched at their outer ends to provide a pair of sparking terminals 21 and, as best seen in Figure 1, said terminals are formed with concave end edges so that a pair of spaced sparking points 22 is formed upon each of the terminals. twenty-four sparking points is provided by the sparking element and, as will be seen, said sparking points will confront the inner wall of the skirt of the shell 10 to provide an equal number of spark gaps between said element and the shell.

porcelain 11 is an annular stop" Thus, a total of Normally, the sparking element 19 will I rest at the lower end of the main electrode 15. However, when the plug is attached to an engine cylinder, in practical use, reciprocation of the piston of the cylinder will serve to reciprocate said element. This reciprocation of the element will, as will be ortion of the electrodebelow the shouldei" 18 clean and free of grease or carbon. Efiicient electrical contact between the elec trode and the sparking element will thus be insured. Furthermore, since the sparking element is freely mounted upon the electrode, said element will also be rotated thereon so that the disposition of the sparking points with respect to the confronting area of'the inner wall of the stantly changed. Thus, from said sparking points shell will serve to burn off any grease or carbon collecting upon the lower margin of the shell at its inner side so that a clean annular area or band will be maintained within the lower end portion of the shell. The current flowing through the main elecsparks jumping,

shell will be 6011- to the wall of the trode will accordingly readily jump from the sparking points of said element to the shell.

In Figure 3 of the drawing, we have illus trated a slight modification of the invention wherein the main electrode of the plug is indicated at 15', the annular stop shoulder thereon at 18 and the sparking element at 19'. lln this modification, a spring 23 is arranged to surround the electrode between the shoulder thereon and the sparking ele ment .for yieldably resisting upward movement of the element upon the electrode and preventing said element from pounding against the shoulder 18. However, as will be seen, the sparking element will be permitted slight reciprocation and will also be free to rotate upon the electrode. Otherwise, the modified structure is identical with the preferred form of the invention.

Having thus described the invention, what is claimed as new is:

1. In a spark plug, the combination of a shell, an electrode insulated with respect to spaced apart in the direction of the axis of P the shell, and a spring resisting upward sliding movement of said element.

2. In a spark plug, the combination 0 shell, an electrode insulated with respect to the shell, a sparking element slidable upon the electrode longitudinally thereof and rovided With sparking points spaced apart in the direction of the axis of the shell, and yieldable means resisting sliding movement of said element to shift one of said sparliing points across the plane of the lower end of the shell.

In testimony whereof We afiix our tures.

Miimaian J. DOWNEY. a MAURICE M. DOWNEY. a JAMES DOWNEY. [n 

